Origin

The fashion term retro is from French rétro, an abbreviation of rétrograde ‘retrograde’ (Late Middle English). This was originally a term in astronomy referring to planets appearing to move in a direction from east to west. It comes from Latin retrogradus, from retro ‘backwards’ and gradus ‘step’. Retro- is also the source of words such as retrospect (early 17th century) from Latin retrospicere ‘look back’ and rear ‘back part’. This was first used as a military term from French arrière ‘behind’, which came from retro. The phrase th'arrear ‘the back’ was mis-analysed as ‘the rear’ and the ‘a’ at the beginning of the word dropped. It was used colloquially to mean ‘buttocks’ from the late 18th century. The other rear,’ to raise up’ and its close relative rise, both Old English, come from an Germanic root, with raise, a Middle English introduction from Old Norse coming from the same source.